Penetrable bed used for cutting sheet material and method for treating same

ABSTRACT

A bed of material provides a supporting surface for supporting sheet material during a cutting process. The bed is used in combination with a cutting apparatus having a cutter and a means for moving the cutter and the bed with respect to each other. The supporting surface is penetrated and cut during the sheet material cutting operation. At least the top layer of the bed material is of such a nature that it may be restored to a substantially uncut or healed condition after having been penetrated and cut to the point where its capacity for properly supporting sheet material is impaired. This restoration may be accomplished by subjecting the bed material to a restoring influence such as heat, ultrasonic waves, or a solvent, or by bonding a thin sheet of plastic or other sheet material to the supporting surface. Particular apparatus combinations are disclosed which will apply the desired restoring mediums at the desired time.

United States Patent 91 Gerber et a1.

[ 1 March 6, 1973 [54] PENETRABLE BED USED FOR CUTTING SHEET MATERIALAND METHOD FOR TREATING SAME [73] Assignee: Gerber Garment Technology,Inc.,

East Hartford, Conn.

[22] Filed: Dec. 3, 1970 [2]] Appl. No.: 94,882

[52] U.S. Cl. ..83/56, 83/169, 83/170, 83/174, 83/658, 83/701, 83/925 CC[51] Int. Cl ..B26d 7/08, B26d 7/10 [58] Field of Search .83/171, 174,658, 659, 925 CC, 83/13, 49, 56,169,170, 701; 156/81, 250

FOREIGN PATENTS OR APPLICATIONS 840,211 l/1939 France ..83/658 PrimaryExaminerJ. M. Meister AttorneyMcCormick, Paulding & Huber 5 7 ABSTRACT Abed of material provides a supporting surface for supporting sheetmaterial during a cutting process. The bed is used in combination with acutting apparatus having a cutter and a means for moving the cutter andthe bed with respect to each other. The supporting surface is penetratedand cut during the sheet material cutting operation. At least the toplayer of the bed material is of such a nature that it may be restored toa substantially uncut or healed condition after having been penetratedand cut to the point where its capacity for properly supporting sheetmaterial is impaired. This restoration may be accomplished by subjectingthe bed material to a restoring influence such as heat, ultrasonicwaves, or a solvent, or by bonding a thin sheet of plastic or othersheet material to the supporting surface. Particular apparatuscombinations are disclosed which will apply the desired restoringmediums at the desired time.

17 Claims, 9 Drawing Figures PATENTED 51973 SHEET 1 BF 3 INVENTORS HElNZ JOSEPH GERBER 0A V/D RA YMOND PEARL a p Azr ozmmrs PATENTED W 1373SHEET 30F 3 VVVVV PENETRABLE BED USED FOR CUTTING SHEET MATERIAL ANDMETHOD FOR TREATING SAME RELATED APPLICATION This application is relatedto subject matter disclosed in the copending US. application, Ser. No.821,723, filed May 5, 1969.

BACKGROUND OF THE INVENTION This invention relates to devices forcutting sheet material such as garment and upholstery materials and thelike, and deals more particularly with a penetrable bed providing asupporting surface for sheet material to be cut and the means andmethods for treating such a bed to periodically restore it to animproved condition.

The general object of this invention is to provide a supporting surfacefor supporting sheet material being cut by a knife or similar cuttingtool and which supporting surface is provided by a bed of materialcapable of being penetrated by the cutting tool during the cuttingprocess and capable of thereafter being treated to restore thesupporting surface to a substantially uncut or healed condition so as toeliminate the necessity of replacing the bed after it becomesexcessively used or worn.

It is another object of this invention to provide a means for effectingthe restoration of the supporting surface while the bed material is inplace relative to the remainder of the cutting apparatus and which isotherwise simple and easy to use.

Another object of this invention is to provide a bed of materialdefining a supporting surface, the top surface layer portion of whichmay be restored through the application of common easily applied andinexpensive mediums such as heat, ultrasonic waves or solvent material.

A further object of this invention is to provide methods for restoringthe top surface layer of a penetrable bed after the bed has been used asa support means during the cutting of sheet material.

Other objects of this invention will appear in the following descriptionand appended claims, reference being made to the accompanying drawingsforming a part of the specification wherein like reference charactersdesignate corresponding parts in the several views.

SUMMARY OF THE INVENTION A penetrable bed of material having arestorable top supporting surface is used in combination with a sheetmaterial cutting apparatus having a cutter with a cutting tool such as areciprocating knife which penetrates and cuts the supporting surfaceduring the cutting process. After the bed has been used throughout aseries of cutting procedures, the supporting surface may be restored forfurther use by applying various types of restoring mediums thereto.

Specific embodiments of this invention include the use of thermoplasticmaterial, in at least the top layer of the bed, which may be restoredthrough the application of heat. The top layer of the bed may also becomposed of a solvent soluble material which may be restored byapplication of a suitable solvent material thereon. Material which issubject to change by ultrasonic waves may also be used for forming thetop layer of the bed. Also a sheet of thin penetrable plastic or othersheet material may be bonded by adhesive or heat to the supportingsurface to effect its restoration.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a fragmentary perspective viewof a sheet material cutting apparatus made in accordance with thisinvention;

FIG. 2 is an enlarged sectional view taken along line 2-1 of FIG. 1;

FIG. 3 is an enlarged, fragmentary sectional view taken along line 3-3of FIG. 1;

FIG. 4 is an enlarged fragmentary side elevational view of the apparatusof FIG. 1 shown partially in section;

FIG. 5 is a view generally similar to FIG. 3 showing a furtherembodiment of the invention;

FIG. 6 is a view generally similar to FIG. 3 showing a furtherembodiment of the invention;

FIG. 7 is a view generally similar to FIG. 1 showing another embodimentof the invention;

FIG. 8 is a view generally similar to FIG. 1 showing a still furtherembodiment of the invention; and

FIG. 9 is a view generally similar to FIG. 2 but shows a furtherapparatus made in accordance with this in-, vention.

DESCRIPTION OF SPECIFIC EMBODIMENTS FIGS. 1 to 4 show one form ofapparatus embodying the present invention. Referring more specificallyto these FIGS, a sheet material or fabric cutting apparatus, generallydesignated 10, includes a table 11 having a bed of material 17 whichprovides a supporting surface 20 for a fabric layup 12 consisting of aplurality of fabric sheets arranged in vertically stacked relation. Awork carriage, generally designated 13, is adapted to move above andparallel to the surface of the table 11 in the coordinate directionsindicated by the arrows X and Y. A cutter 15 having a reciprocatingcutting blade 16 is mounted on the carriage 13 so that it can be drivento and from any predetermined point on the table surface and along anydesired line of cut relative to the fabric layup 12. The blade 16extends downwardly from the main body of the cutter l5 and isreciprocated vertically by a motor in the cutter body. It may also berotated about a vertical 0 axis by another motor in the cutter body forthe purpose of maintaining the blade tangent to the line of cut. Thecutter may also be raised and lowered bodily, by another motor, to movethe cutting blade out of and into cutting engagement with the fabriclayup, FIG. 1 showing the cutter in its lowered position at which theblade is in cutting engagement with the fabric.

A main carriage 25 is movably mounted on racks 14, 14, thereby providingmovement for the cutter along the longitudinal dimension of table 11 orin the X coordinate direction. The work carriage 13 is movably mountedon a guide bar or tube 26 and a lead screw 34, of the main carriage 25,which extend transversely of the table 11. Movement of the carriage 13along the guide bar 26, as driven by the lead screw 34, is in the Ycoordinate direction.

The main carriage 25 includes a drive shaft (not shown) which extendstransversely of the table 11 and which has pinions at its opposite endsfor engaging the racks 14, 14. Movement of the main carriage 25 is cffected in response to operation of a drive motor (not shown) which isconnected to the main carriage drive shaft. The work carriage 13 movestransversely of the table in response to the operation of another guidemotor (not shown) which is operably connected to the lead screw 34.

The movement of the carriages 13 and 25 may be effected in response topositioning signals supplied through the cable 24 by an associated inputmeans such as, for example, a numerically controlled controller or acomputer (not shown). THe carriages 13 and 25 are capable of moving theblade 16 is cutting engagement with the layup 12 along any line whichmay be straight or curved as required in cutting a garment component orthe like. When in cutting engagement with the fabric layup, the blade 16during at least a portion of its stroke penetratesthe upper supportingsurface 20 of the table 11. Except for the construction of the bed 17and the means for periodically restoring its supporting surface 20, ashereinafter described, the construction and operation of the cuttingapparatus is or may be similar to that described in copendingapplication, Ser. No. 821,723, filed May 5, 1969, to which reference maybe made for further details.

The invention of this particular application is directed specifically tothe use of a penetrable bed 17 i in the table 11 having a restorablesupporting surface 20, and to means and methods for effecting suchrestoration. In the table 11 of FIG. 1, the bed 17 is disposed in aframe having a bottom wall 22 and side and end walls (not numbered)which extend upwardly from the bottom wall 22 to form a shallowcontainer. The bed 17 may, if desired, be formed from a plurality ofgenerally rectangular blocks, the broken lines in FIG. 1 indicating theboundaries of such blocks.

The bed 17 of FIG. 1 is one which is constructed so as to enable itssupporting surface to be restored by means of heat. In particular, theillustrated bed 17 includes a base portion 19, a body portion 18 made ofa material readily penetrable by the blade 16, and a top thin layer orskin 21 made of a thermoplastic material having a relatively low meltingpoint. The material from which the layer 21 is made is one which whenapplied as a thin layer or skin to the body portion 18 is readilypenetrable by the knife blade 16 even though it may not be readilypenetrable by the blade if formed into thicker sheets or blocks. InFIGS. 1 to 4 the thickness of the layer 21 is exaggerated for purposesof clarity and it should be understood that, depending on the materialused for forming this layer, its thickness is sufficiently small that itmay be readily penetrated with ease by the knife blade. Variousdifferent low melting point resins and plastics may be used to form thislayer. The material of the body portion 18 may be any one of variousdifferent materials which are capable of providing the bed 17 with somedepth, to accommodate the portion of the knife blade which extends belowthe supporting surface 20, and through which the blade may pass withcomparative ease. In the illustrated case this material is taken to befelt made of relatively loosely compacted fibers and formed into blocksor strips which blocks or strips are arranged on end and attached byglue to the base 19. As an alternative the body portion 18 may be madeof a cellular plastic material having a substantially higher meltingpoint than the melting point of the material of which the top layer 21is made. In FIG. 1 the base portion 19 is used to hold in assembly theindividual strips or blocks of felt of the body portion 18, and in caseswhere the body portion 18 is made of larger individual pieces ofmaterial, the base portion 19 may be omitted.

As mentioned above, in the specific embodiment disclosed in FIGS. 1 to4, the body portion 18 of the bed 17 is composed of relatively looselyconstituted felt and has a coating or layer 21 of thermoplastic materialon its upper surface and defining the supporting surface 20 of the bed.Actually, the thermoplastic material in making the bed 17 is applied tothe felt body portion in a melted state and may actually be absorbed bythe top portion of the felt body 18 so that the restorable surface layeror skin 21 becomes a composite structure made of the felt fibers and thethermoplastic material. In any event, the top surface layer 21 of thebed is penetrated by the knife blade 16, as shown in FIGS. 2 and 4during a cutting operation, and after the performance of many cuttingoperations the upper portion of the bed 17 may become so cut up alongclosely adjacent and intersecting lines that the bed no longer presentsto the layup a continuous firm supporting surface but instead forms asurface divided into many separate discrete portions which are capableof moving and deforming relative to one another and which thereby allowthe fabric of the layup to shift and deform in an undesirable manneras'it is being cut. Once the bed 17 reaches such a state that it nolonger provides desirable support for the material or cloth being cut,the upper layer or skin 21 is subjected to heat to melt or soften thethermoplastic material making up such layer and to refuse together thepreviously cut portions of such layer to again form a continuous firmsurface.

The means by which heat is applied to the bed 17 to melt or soften thethermoplastic material of the layer 21 may take various different formswithout departing from the broader aspects of this invention. In theembodiment of FIGS. 1 to 4, this means comprises a plurality of heatlamps 30, 30 which are carried bya bar 29 attached to the main carriage28 and extending transversely of the table 11. The heat lamps 30, 30 aredisposed with their output faces directed toward and spaced somedistance from the supporting surface 20 and when it is desired torestore the supporting surface 20 these lamps are turned on and thecarriage 28 is slowly moved from one end to the other of the table 1 1.By properly selecting the rate of movement of the carriage 28 duringthis process, the heat lamps may be caused to heat the upper portion 20of the bed to the optimum degree required to weld or refuse together thecut portions of the surface 21 and to restore it to its originalcondition as existing before any cutting had taken place.

In the apparatus of FIG. 1, the heat lamps 30, 30 are, as mentioned,attached to the main carriage 28 for movement therewith. Since theseheat lamps are used only infrequently to restore the supporting surface20, they may, if desired, be mounted on another carriage separate fromthe main carriage 25, and this separate carriage for the heat lamps may,if desired, be a relatively simple carriage designed to be moved alongthe length of the table 11 by hand. It may also be designed for easyattachment to and removal from the table 11 so as to enable it to beattached to the table only when needed to restore the supporting surfaceand to enable its use with a number of individual tables. It will ofcourse be understood that in place of heat lamps 30, 30 various otherheating means may be employed, such as electrical resistance heatingunits.

In addition to the use of heat for restoring a bed having athermoplastic upper surface layer, various other different means andmethods may be used for restoring the supporting surface of a sheetmaterial cutting device in accordance with this invention. FIG. 5, forexample, shows a device in which the supporting surface is restored byspraying a solvent onto it. Referring to this FIG., the illustrated bed17a is substantially similar to the bed 17 of FIG. 1 except forincluding, in place of the thermoplastic upper layer or skin 21 of FIG.1, and upper layer or skin 34 made of a material which is readilysoluble by a suitable solvent. The remainder of the bed 170 may includea body portion 18 similar to the body portion 18 of FIG. 1 and a base 19similar to the base 19 of FIG. 1. After the bed 17a becomes cut to anundesirable degree, restoration of the cut top surface layer 34 iseffected through the use of a carriage 31 which may be part of the maincarriage or a separate unit. A supply of solvent material is applied tothe carriage 31 and is applied to the top surface layer 34 of the bed17a through a plurality of nozzles 33, 33 disposed along a conduit 34carried by the carriage 31 and extending transversely of the bed 17a. Asthe solvent is sprayed from the nozzles 33, 33 the carriage 31 is movedlongitudinally along the length of the table from one end to another.The solvent puts at least some of the material of the layer 34 intosolution and after the solvent thereafter evaporates it leaves behind anewly reformed upper layer 34 which is restored to substantially thesame condition as existed before any cutting had taken place.

FIG. 6 shows another embodiment of the invention which uses ultrasonicwave energy for restoring the top layer of the supporting bed. As shownin this FIG., the illustrated apparatus is substantially similar to thatof FIG. 3 except that the penetrable bed 17b includes an upper layer 42of material, substituted for the layer 21 of FIG. 3, which is of a typewhich changes its physical state from a solid or semisolid to a liquidor semiliquid in the presence of ultrasonic wave energy and whichreturns to its solid or semisolid state when the ultrasonic wave energyis removed. Cooperating with the bed 17b of FIG. 7 are a plurality ofultrasonic wave generators 44, 44 carried by a support member 46extending transversely of the bed 17b and carried by a carriage 46 formovement longitudinally of the bed. When it is desired to restore thesurface of the bed 17b, the ultrasonic wave generators 44, 44 are turnedon and act to direct ultrasonic wave energy onto the surface 42, and asthe generators are turned on the carriage is moved longitudinally fromone end to the other of the bed 17b to treat the entire upper surface ofthe bed. It will be understood that as the material of the top surfacereceives the ultrasonic wave energy it is transformed temporarily to aliquid or semiliquid state which causes the cut areas thereof to flowtogether and after the receipt of the wave energy is terminated thematerial resolidifies to refuse the surface into a single continuousform.

In addition to restoring the supporting surface of a penetrable bed bytreating the upper surface layer of the material of such bed, thesupporting surface may also be restored by adding to the supportingsurface new material which bonds together the cut portions of the bedand which itself forms a new surface. One method and apparatus foreffecting restoration in this manner is shown by way of example in FIG.7. Referring to this FIG., a table is shown at 50 and includes a bed ofpenetrable material 52 which is taken to be a cellular foamed plasticsuch as Ethofoam, but which could also take various other differentforms of easily penetrated material such as loosely compacted felt. Thelines indicated at 54, 54 represent previous lines of cut made in andthrough the original supporting surface 56 of the bed 52. In order torestore the cut supporting surface 56, a thin sheet 58 of thermoplasticmaterial is spread over the surface 56 and is then heated to a degreesufficient to cause it to bond, after removal of the heat, to thematerial of the bed 52. That is, by properly controlling the heatapplied to the sheet 58, it may be made to melt slightly and to a degreesufficient to cause it to weld or bond to the material of the bed 52without destroying its continuity. Therefore, after the heat is removed,the sheet 58 in effect becomes part of the bed 52 and forms a newcontinuous surface for such bed. As shown in FIG. 7, the heat used tobond the sheet 52 to the bed 52 may be provided by a row of heat lamps60, 60 carried by the carriage 25.

In addition to the sheet 58 being made of a ther moplastic material andbonded to the bed 52 by means of heat, sheets of the same or differentmaterial as the sheet 58 may also be used and may be bonded to thesurface 56 of the bed 52 by means of suitable adhesive, the adhesivefirst being applied to the surface 56 and the sheet thereafter beingplaced over the adhesive coated surface. Also, instead of using aperformed sheet, a hardenable liquid, such as an epoxy resin with anappropriate catalyst, may be spread over the cut supporting surface andthereafter hardened to form a new continuous supporting surface.

In the above embodiments of the invention utilizing heat as a medium forrestoring the supporting surface of the penetrable bed, the heat hasbeen applied by localized heating means moved relative to the table. Ifdesired, however, the heat may also be applied by various heating meansbuilt into the body of the table 11 and adapted to heat at one time thefull extent of the supporting surface or at least large zones of suchsurface. One such apparatus is shown in FIG. 8 in which the heating ofthe illustrated bed 60 is effected by an electric resistance heatingelement 62 incorporated in the bed 60. The illustrated element 62 is inthe form of a wire extending in many loops throughout the length of thebed 60 so as when it is energized it substantially uniformly heats theentire extent of the bed, the element 62 being located below the levelof the maximum penetration of the knife 16. Except for the addition ofthe heating element 62 and the omission of the heat lamps 30, 30, theapparatus of FIG. 8 is substantially similar to that of FIG. 1, andparts of FIG. 8 which are similar to those of FIG. 1 have been given thesame reference numerals as in FIG. 1 and need not be redescribed.

In the embodiments of the invention described above the fabric layup 12has been supported on the supporting surface 20 of the bed byprincipally its own weight. In many cases it may be desirable to add anadditional holding influence to the layup to prevent its shifting duringthe cutting operation, and one very desirable means for effecting suchholding influence involves the use of an air impervious sheet coveringthe layup and acting in conjunction with a vacuum means for evacuatingthe space between the air impervious sheet and the supporting surface sothat atmospheric pressure acting on the outside of the air impervioussheet forces it toward the supporting surface and causes it to hold thelayup in a relatively rigid condition.

This general concept of a vacuum holddown for a fabric layup isdisclosed in US. Pat. No. 3,495,492 to which reference may be made forfurther details of such a means. As shown in this patent, the means forevacuating the space between the supporting surface and the airimpervious sheet includes a vacuum chamber located below the penetrablebed and air passages extending through the bed material from thesupporting surface to the vacuum chamber. In cases, such as describedabove, wherein the bed includes a restorable upper layer defining thesupporting surface, it may be difficult to retain air passages throughthe bed as the surface layer is restored. Therefore, where it isdesirable to use a vacuum holddown means in combination with a bedhaving a restorable supporting surface, the difficulty in maintainingair passages through the penetrable bed may be circumvented by designingthe evacuating means so as to withdraw air from the edges of the layuprather than from the bottom of the layup and through the bed material.One arrangement for doing this is shown, by way of example, in FIG. 9.

Referring to FIG. 9, the apparatus there shown includes a table 1 laincluding a bed of penetrable material 17 similar to the bed 17 ofFIG. 1. Below the wall 22 the table 1 la includes a vacuum chamber 39connected to a suitable source of vacuum through a conduit 40. The upperwall 22 of the vacuum chamber extends outwardly, on both sides, beyondthe longitudinal edges of the bed 17, and outboard of the bed 17, oneach side, includes a number of passages 38, 38 passing through the wall22. Positioned above the passages 38, 38 and extending along the lengthof the longitudinal edges of the bed 17 are two side blocks 37, 37 ofair permeable material such as loose fibered felt or open celled foamedplastic. In FIG. 9 only a few of the passages 38, 38 are illustrated butit should be understood that the table 11a includes a large number ofsuch passages arranged along the full length of the table on either sidethereof so that along the full length of the table the side blocks 37,37 are subjected to the vacuum of the vacuum chamber. Each side block 37extends upwardly beyond the supporting surface 20 of the bed 17 and intoadjacent relationship to the associated longitudinal edge of the layup12. An air impervious plastic sheet 36 is placed over the top of thelayup l2 and also extends over the side blocks 37, 37 and downwardlyinto overlying relationship withthe side walls of the table 110. When avacuum is applied to the vacuum chamber 39 through the conduit 40, airis withdrawn through the air permeable blocks 37, 37 and through thepassages 38, 38 to evacuate the space between the supporting surface 20and the air impervious plastic sheet 36 with the result that atmosphericpressure acting on the top of the sheet presses it downwardly toward thesupporting surface to holdthe material of the layup firmly in place. Itis here assumed that the material of the layup 12 is relatively airpermeable so that when vacuum is applied to the vacuum chamber the airtrapped in the layup may be withdrawn laterally through the material ofthe layup. In cases where the material of the layup consists ofrelatively air impervious sheets, such as sheets of plastic, an airconducting means such as a sheet of cor-- rugated cardboard or a sheetof air permeable material may be sandwiched between the air imperviousplastic sheet 36 and the top surface of the layup 12 to permitevacuation of the space therebetween and to achieve the desired holddownby atmospheric pressure.

We claim:

1. In a sheet material cutting apparatus the combination comprisingmeans providing a supporting surface for supporting in a spreadcondition sheet material to be cut, a cutter having a cutting tool, andmeans for supporting and moving said cutter and said supporting surfacerelative to one another in such a manner that during a cutting operationsaid cutting tool passes through and cuts the material on saidsupporting surface and penetrates said supporting surface and so thatsaid cutting tool is movable relative to said supporting surface along adesired line of cut, such that said cutter is translated on a locus ofpoints lying in a plane substantially parallel to said sheet materialduring said cutting operation, said means providing a supporting surfacecomprising a bed of material including a body portion made of materialreadily penetrable by said cutting tool, and a skinlike top layer ofmaterial superimposed on said portion and directly forming saidsupporting surface, said cutting tool during a cutting operation passingthrough said top layer and penetrating said body portion of said bed,said top layer being made of a material which is restorable through theaction of a restoring medium to heal cuts therein after having beenpenetrated and cut by said cutting tool during a cutting operation.

2. The combination defined in claim 1 further characterized by said toplayer of said bed including a thermoplastic material, and means forperiodically heating said top layer to restore said supporting surface.

3. The combination defined in claim 2 further characterized by said bodyportion of said bed being made of a fibrous material.

4. The combination defined in claim 1 further characterized by said toplayer of said bed including a solvent soluble material which isrestorable by the application of a solvent material, and means forperiodically applying a solvent to said top layer to restore saidsupporting surface.

5. In a sheet material cutting apparatus the combination comprisingmeans providing a supporting surface for supporting in a spreadcondition sheet material to be cut, a cutter having a cutting tool,means for supporting and moving said cutter and said supporting surfacerelative to one another in such a manner that during a cutting operationsaid cutting tool passes through and cuts the material on saidsupporting surface and penetrates said supporting surface and so thatsaid cutting tool is movable relative to said supporting surface along adesired line of cut, said means providing a supporting surfacecomprising a bed of material including a body portion made of a materialreadily penetrable by said cutting tool, and a top layer of materialsuperimposed on said body portion and directly forming said supportingsurface, said top layer of said, bed including a material which isrestorable by the application of ultrasonic -wave energy thereto to healcuts therein after having been penetrated and cut by said cutting toolduring a cutting operation, and means for periodically applyingultrasonic wave energy to said layer to effect a restoration of saidsupporting surface.

6. A supporting surface defining a bed of material for use in a sheetmaterial cutting apparatus of the type which utilizes a reciprocatingblade or similar cutting tool which is translated substantially normalto the direction of reciprocation of said blade and which cuts thesupporting surface and penetrates the bed by a given distance during acutting operation, said bed comprising: a body portion made of amaterial readily penetrable by a cutting tool, and a relatively thinskinlike top surface layer portion overlying said body portion anddirectly defining said supporting surface and made of material capableof being restored to a continuous state through the application of arestoring medium after it has been cut during a cutting operation, saidtop surface layer portion having a thickness substantially less thansaid given distance by which said cutting tool penetrates said bedwhereby said cutting tool in penetrating said bed passes completelythrough said top surface layer portion and penetrates said body portionwhile cutting along a locus of points lying in a plane substantiallynormal to the direction of reciprocation of said blade.

7. A bed as defined in claim 6 further characterized by said top surfacelayer portion being made of a thermoplastic material which may berestored by the application of heat thereto.

8. A bed as defined in claim 7 further characterized by said bodyportion thereof being made of felt, and said top surface layer portionincluding a thermoplastic material.

9. A bed as defined in claim 6 further characterized by said top surfacelayer portion comprising a solvent soluble material which is restorableby the application of a solvent thereto after a cutting operation.

10. A supporting surface defining bed of material for use in a sheetmaterial cutting apparatus of the type which utilizes a reciprocatingblade or similar cutting tool which penetrates and cuts the supportingsurface during a cutting operation, said bed comprising: a relativelythick body portion made of a material readily penetrable by a cuttingtool, and a relatively thin top surface layer portion directly definingsaid supporting surface and made of a material which is restorable to acontinuous state by the application of ultrasonic wave energy theretoafter it has been cut during a cutting operation.

11. A method for cutting sheet material by means of a reciprocatingcutting tool which method comprises the steps of providing a bed havinga body portion made from a material readily penetrable by a cutting tooland a skinlike surface layer portion overlying said body portion,translating said reciprocating cutting tool substantially normal to thedirection of reciprocation of said cutting tool in the region adjacentto said cutting tool during each of said strokes, said skinlike surfacelayer portion defining a supporting surface and being made from amaterial which is restorable through the' action of a restoring mediumto heal cuts therein after having been penetrated and cut by a cuttingtool during a cutting operation, placing sheet material to be cut onsaid supporting surface, cutting said sheet material with areciprocating cutting tool cutter which during each stroke passesthrough and cuts booth said sheet material and said skin-like surfacelayer portion and which penetrates and cuts said supporting surface saidbody portion, and thereafter restoring said skinlike surface layerportion supporting surface to heal the cuts made in said supportingsurface therein by said cutting tool and to render it substantiallycontinuous for use in a subsequent cutting operation.

12. The method defined in claim 11 further characterized by said step ofproviding a bed involving the provision of a bed having a skin-likesurface layer portion made of a thermoplastic material, and said step ofrestoring said supporting surface being accomplished by heating saidsurface layer portion of said bed to soften the material thereof to thepoint where the material on opposite sides of cuts therein is united andthen removing the heat to allow said material to resolidify to acontinuous state.

13. The method defined in claim 11 further characterized by said step ofproviding a bed involving the provision of a bed having a skinlikesurface layer portion made of a solvent soluble material, and said stepof restoring said surface being accomplished by applying a solvent tosaid surface layer portion of said bed.

14. A method for cutting sheet material which method comprises the stepsof providing a bed of material having a supporting surface, placingsheet material to be cut on said supporting surface, cutting said sheetmaterial with a cutter which passes through said sheet material andpenetrates and cuts said supporting surface, and thereafter restoringsaid supporting surface to heal the cuts made therein by said cuttingtool and to render it substantially continuous for use in a subsequentcutting operation, said step of providing a bed involving the provisionof a bed having a surface layer portion defining said supporting surfacewhich surface layer portion is made of a material which changes statefrom substantially a solid to substantially a liquid in the presence ofultrasonic wave energy, and said step of restoring said surface beingaccomplished by exposing said surface layer portion of said bed toultrasonic wave energy.

15. A method for cutting sheet material which method comprises the stepsof providing a bed of material having a supporting surface, placingsheet material to be cut on said supporting surface, cutting said sheetmaterial with a cutter which passes through said sheet material andpenetrates and cuts said supporting surface, and thereafter restoringsaid supporting surface to heal the cuts made therein by said cuttingtool and to render it substantially continuous for use in a subsequentcutting operation, said step of restoring said supporting surface beingaccomplished by spreading a sheet of thermoplastic material over saidsurface and thereafter heating said sheet to bond it to said supportingsurface.

ing an adhesive to said supporting surface and thereafter applying athin sheet of material over said supporting surface so as to be bondedthereto by said adhesive.

17. The method defined in claim 11 further characterized by said step ofrestoring said supporting surface being accomplished by spreading oversaid supporting surface a hardenable liquid, and thereafter hardeningsaid hardenable liquid.

1. In a sheet material cutting apparatus the combination comprisingmeans providing a supporting surface for supporting in a spreadcondition sheet material to be cut, a cutter having a cutting tool, andmeans for supporting and moving said cutter and said supporting surfacerelative to one another in such a manner that during a cutting operationsaid cutting tool passes through and cuts the material on saidsupporting surface and penetrates said supporting surface and so thatsaid cutting tool is movable relative to said supporting surface along adesired line of cut, such that said cutter is translated on a locus ofpoints lying in a plane substantially parallel to said sheet materialduring said cutting operation, said means providing a supporting surfacecomprising a bed of material including a body portion made of materialreadily penetrable by said cutting tool, and a skinlike top layer ofmaterial superimposed on said portion and directly forming saidsupporting surface, said cutting tool during a cutting operation passingthrough said top layer and penetrating said body portion of said bed,said top layer being made of a material which is restorable through theaction of a restoring medium to heal cuts therein after having beenpenetrated and cut by said cutting tool during a cutting operation. 1.In a sheet material cutting apparatus the combination comprising meansproviding a supporting surface for supporting in a spread conditionsheet material to be cut, a cutter having a cutting tool, and means forsupporting and moving said cutter and said supporting surface relativeto one another in such a manner that during a cutting operation saidcutting tool passes through and cuts the material on said supportingsurface and penetrates said supporting surface and so that said cuttingtool is movable relative to said supporting surface along a desired lineof cut, such that said cutter is translated on a locus of points lyingin a plane substantially parallel to said sheet material during saidcutting operation, said means providing a supporting surface comprisinga bed of material including a body portion made of material readilypenetrable by said cutting tool, and a skinlike top layer of materialsuperimposed on said portion and directly forming said supportingsurface, said cutting tool during a cutting operation passing throughsaid top layer and penetrating said body portion of said bed, said toplayer being made of a material which is restorable through the action ofa restoring medium to heal cuts therein after having been penetrated andcut by said cutting tool during a cutting operation.
 2. The combinationdefined in claim 1 further characterized by said top layer of said bedincluding a thermoplastic material, and means for periodically heatingsaid top layer to restore said supporting surface.
 3. The combinationdefined in claim 2 further characterized by said body portion of saidbed being made of a fibrous material.
 4. The combination defined inclaim 1 further characterized by said top layer of said bed including asolvent soluble material which is restorable by the application of asolvent material, and means for periodically applYing a solvent to saidtop layer to restore said supporting surface.
 5. In a sheet materialcutting apparatus the combination comprising means providing asupporting surface for supporting in a spread condition sheet materialto be cut, a cutter having a cutting tool, means for supporting andmoving said cutter and said supporting surface relative to one anotherin such a manner that during a cutting operation said cutting toolpasses through and cuts the material on said supporting surface andpenetrates said supporting surface and so that said cutting tool ismovable relative to said supporting surface along a desired line of cut,said means providing a supporting surface comprising a bed of materialincluding a body portion made of a material readily penetrable by saidcutting tool, and a top layer of material superimposed on said bodyportion and directly forming said supporting surface, said top layer ofsaid bed including a material which is restorable by the application ofultrasonic wave energy thereto to heal cuts therein after having beenpenetrated and cut by said cutting tool during a cutting operation, andmeans for periodically applying ultrasonic wave energy to said layer toeffect a restoration of said supporting surface.
 6. A supporting surfacedefining a bed of material for use in a sheet material cutting apparatusof the type which utilizes a reciprocating blade or similar cutting toolwhich is translated substantially normal to the direction ofreciprocation of said blade and which cuts the supporting surface andpenetrates the bed by a given distance during a cutting operation, saidbed comprising: a body portion made of a material readily penetrable bya cutting tool, and a relatively thin skin-like top surface layerportion overlying said body portion and directly defining saidsupporting surface and made of material capable of being restored to acontinuous state through the application of a restoring medium after ithas been cut during a cutting operation, said top surface layer portionhaving a thickness substantially less than said given distance by whichsaid cutting tool penetrates said bed whereby said cutting tool inpenetrating said bed passes completely through said top surface layerportion and penetrates said body portion while cutting along a locus ofpoints lying in a plane substantially normal to the direction ofreciprocation of said blade.
 7. A bed as defined in claim 6 furthercharacterized by said top surface layer portion being made of athermoplastic material which may be restored by the application of heatthereto.
 8. A bed as defined in claim 7 further characterized by saidbody portion thereof being made of felt, and said top surface layerportion including a thermoplastic material.
 9. A bed as defined in claim6 further characterized by said top surface layer portion comprising asolvent soluble material which is restorable by the application of asolvent thereto after a cutting operation.
 10. A supporting surfacedefining bed of material for use in a sheet material cutting apparatusof the type which utilizes a reciprocating blade or similar cutting toolwhich penetrates and cuts the supporting surface during a cuttingoperation, said bed comprising: a relatively thick body portion made ofa material readily penetrable by a cutting tool, and a relatively thintop surface layer portion directly defining said supporting surface andmade of a material which is restorable to a continuous state by theapplication of ultrasonic wave energy thereto after it has been cutduring a cutting operation.
 11. A method for cutting sheet material bymeans of a reciprocating cutting tool which method comprises the stepsof providing a bed having a body portion made from a material readilypenetrable by a cutting tool and a skinlike surface layer portionoverlying said body portion, translating said reciprocating cutting toolsubstantially normal to the direction of reciprocation of said cuttingtool in the region adjacent to said cutting tool during each of saidstrokes, said skinlike surface layer portion defining a supportingsurface and being made from a material which is restorable through theaction of a restoring medium to heal cuts therein after having beenpenetrated and cut by a cutting tool during a cutting operation, placingsheet material to be cut on said supporting surface, cutting said sheetmaterial with a reciprocating cutting tool cutter which during eachstroke passes through and cuts booth said sheet material and saidskin-like surface layer portion and which penetrates and cuts saidsupporting surface said body portion, and thereafter restoring saidskinlike surface layer portion supporting surface to heal the cuts madein said supporting surface therein by said cutting tool and to render itsubstantially continuous for use in a subsequent cutting operation. 12.The method defined in claim 11 further characterized by said step ofproviding a bed involving the provision of a bed having a skin-likesurface layer portion made of a thermoplastic material, and said step ofrestoring said supporting surface being accomplished by heating saidsurface layer portion of said bed to soften the material thereof to thepoint where the material on opposite sides of cuts therein is united andthen removing the heat to allow said material to resolidify to acontinuous state.
 13. The method defined in claim 11 furthercharacterized by said step of providing a bed involving the provision ofa bed having a skinlike surface layer portion made of a solvent solublematerial, and said step of restoring said surface being accomplished byapplying a solvent to said surface layer portion of said bed.
 14. Amethod for cutting sheet material which method comprises the steps ofproviding a bed of material having a supporting surface, placing sheetmaterial to be cut on said supporting surface, cutting said sheetmaterial with a cutter which passes through said sheet material andpenetrates and cuts said supporting surface, and thereafter restoringsaid supporting surface to heal the cuts made therein by said cuttingtool and to render it substantially continuous for use in a subsequentcutting operation, said step of providing a bed involving the provisionof a bed having a surface layer portion defining said supporting surfacewhich surface layer portion is made of a material which changes statefrom substantially a solid to substantially a liquid in the presence ofultrasonic wave energy, and said step of restoring said surface beingaccomplished by exposing said surface layer portion of said bed toultrasonic wave energy.
 15. A method for cutting sheet material whichmethod comprises the steps of providing a bed of material having asupporting surface, placing sheet material to be cut on said supportingsurface, cutting said sheet material with a cutter which passes throughsaid sheet material and penetrates and cuts said supporting surface, andthereafter restoring said supporting surface to heal the cuts madetherein by said cutting tool and to render it substantially continuousfor use in a subsequent cutting operation, said step of restoring saidsupporting surface being accomplished by spreading a sheet ofthermoplastic material over said surface and thereafter heating saidsheet to bond it to said supporting surface.
 16. A method for cuttingsheet material which method comprises the steps of providing a bed ofmaterial having a supporting surface, placing sheet material to be cuton said supporting surface, cutting said sheet material with a cutterwhich passes through said sheet material and penetrates and cuts saidsupporting surface, and thereafter restoring said supporting surface toheal the cuts made therein by said cutting tool and to render itsubstantially continuous for use in a subsequent cutting operation, saidstep of restoring said supporting surface being accomplished by applyingan adhesive to said supporting surface and thereafter applying a thinsheet of material over said supportIng surface so as to be bondedthereto by said adhesive.